These results agree with the growth of the transcrystalline
regions at the SCF surfaces: The latter, because of its low amount, need of very little PP amorphous phase as to be imbibed and then the highest PP supply to the transcrystalline
regions growing around each fiber.
The results showed that transcrystalline
structures formed in the inner layers of the WAIM PP/SAN blend parts at the SAN contents of 4, 6, and 8 wt%, but were absent at an SAN content of 2 wt%.
At 1,8 spot power the structure of the parent metal consists in big dendrites with different orientation, and in welded metal many cracks with transcrystalline
propagation, length 200[micro]m and distance about 5-8[micro]m, figure 4b.
Effect of transcrystalline
morphology on interfacial adhesion in cellulose/polypropylene composites.
For the produced coatings brittle inter- and transcrystalline
fracture are characteristic.
In the case of samples prepared by injection molding of PP/EPR blends, depth-profiling studies have revealed the formation of a skin consisting of several layers ("stratification"), whose composition is different compared to the bulk phase (8,9,28); a transcrystalline
layer (~~10 [micro]m thick) followed by an elastomer region (~~20 [micro]m thick) were detected in the outer regions of these samples.
Contrary to this, transcrystalline
cleavage cracks (Type 2) which formed during loading remained closed.
Furthermore, at 130[degrees]C the surface which is in direct contact with the chill roll shows transcrystalline
structures (grown crystalline structures that can develop if the polymer melt gets in direct contact with the mold at quiescent conditions due to the high amount of nuclei at the mold).
Mixed surface with brittle aspect, by cleavages having transcrystalline
and intergrain propagation.
In the failure transcrystalline
fracture over seam metal and diffusion zone was combined with tough fracture of the base metal (see Figure 11, a, d).
In one study, Ryntz and Ramamurthy (4) found that a thin transcrystalline
PP region developed at the TPO surface of an injection-molded PP/EPR blend.
Formation of transcrystalline
regions in polypropylene was found to be directly related to the geometrical morphology or surface roughness of the mold.